At age 28, he formed his own production company and set to work on his directorial debut, "A Small Circle of Friends" (1980), a nostalgic comedy set at Harvard (Cohen's alma mater) in the 60s, starring Brad Davis and Karen Allen and more than inspired by Francois Truffaut's superior "Jules et Jim" (1962). Cohen followed with "Scandalous" (1984), a farce starring Robert Hays and John Gielgud. He also executive produced the high-minded remake of "The Razor's Edge" (1984), starring a miscast Bill Murray, and produced the teen drama "The Legend of Billy Jean" (1985).

By 1985, Cohen had become a significant director of TV commercials and programs, with credits including "Miami Vice", "A Year in the Life" and "thirtysomething". He juggled these tasks with ongoing feature production as the president and, later, vice chairman and partner of Keith Barish Productions. In this capacity, he produced or executive produced such diverse fare as Paul Schrader's "Light of Day" , with Michael J Fox and Gena Rowlands, the sci-fi thriller "The Running Man", the sober and atmospheric "Ironweed" (all 1987), and Wes Craven's creepy tale of voodoo, "The Serpent and the Rainbow" (1988).

In October 1988, Cohen and longtime friend John Badham merged their two separate deals with MCA to form The Badham/Cohen Group. Their first two ventures were slickly produced star packages, "Bird on a Wire" (1990), with Mel Gibson and Goldie Hawn, and "The Hard Way" (1991), with James Woods and Michael J Fox. Cohen continued to work in 90s TV, racking up credits on "Eddie Dodd", "The Antagonists" and "The Wonder Years". He returned to feature directing with the fanciful biopic "Dragon: The Bruce Lee Story" (1993), a surprise critical and commercial hit (which Cohen co-wrote). Featuring an inspirational central performance by the half-Hawaiian Jason Scott Lee, the film confounded easy categorization. Nearly equal parts old-fashioned biography, touching romance, sensitive problem pic (dealing with anti-Asian prejudice and the strains of interracial romance) and rousing chopsocky adventure, the film delighted even those with no interest in martial arts.

Cohen returned to the small screen in a producing capacity, serving as executive producer, creator, screenwriter and--fleetingly--performer on a series of "Vanishing Son" TV-movies as part of the syndicated "Action Pack" series in 1994. The original, its three sequels and a 1995 syndicated spin-off series--a routinely inferior modern-day fusion of "Kung Fu," "The Incredible Hulk" and "The Fugitive"--well displayed Cohen's interest in issues confronting Asian immigrants in the US. "Vanishing Son" began in mainland China where two brothers caught up in the turmoil of the Tiananman Square demonstrations are forced to flee for the safety of the US. The elder, Jian-Wa (Russell Wong), is torn between a career as a concert violinist and further developing his already formidable martial arts skills. The younger, Wago (Chi Muoi Lo), mesmerized by glitz and power, becomes a gangster. Like "Dragon," the "Vanishing Son" movies were sometimes corny yet satisfying offerings of romance, social commentary and impressive fighting sequences.

After the success of his Bruce Lee biopic, Cohen shifted gears considerably to helm "Dragonheart" (1996), a big-budget, special effects-driven period fantasy. Dennis Quaid played an itinerant dragonslayer who teams with Draco (memorably voiced by Sean Connery), the last dragon on Earth, to bring down a tyrannical king (David Thewlis). Reviews were wildly mixed and business was disappointing. Nonetheless, Cohen remained on the A-list, directing Sylvester Stallone in the high-profile disaster thriller "Daylight" (1996). Cohen directed a few television projects including the television series, "The Guardian" (1997) and the HBO drama, "The Rat Pack" (1998). He then returned back to the big screen to direct two summer blockbusters, "The Fast And The Furious" (2001) and "xXx" (2002) both servicable but unambitious vehicles starring then-rising action star Vin Diesel. Dumbing things down even further, Cohen's next effort was "Stealth" (2005), a stupefyingly lowbrow cross between "Top Gun" and "2001" about a troika of fighter pilots (Jamie Foxx, Josh Lucas and Jessica Biel) of a new generation stealth plane.